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Change union to vcache. Use address of the union node as key.

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It would be better to use (uppervp, lowervp) as key, but either
may be NULL and may change any time.
This commit is contained in:
hannken 2015-02-16 10:22:00 +00:00
parent c20c5717d4
commit 8596fa407f
3 changed files with 120 additions and 117 deletions
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5
sys/fs/union/union.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: union.h,v 1.27 2015/02/16 10:21:25 hannken Exp $ */ /* $NetBSD: union.h,v 1.28 2015/02/16 10:22:00 hannken Exp $ */
/* /*
* Copyright (c) 1994 The Regents of the University of California. * Copyright (c) 1994 The Regents of the University of California.
@ -121,6 +121,7 @@ struct union_node {
kmutex_t un_lock; kmutex_t un_lock;
LIST_ENTRY(union_node) un_cache; /* c: Hash chain */ LIST_ENTRY(union_node) un_cache; /* c: Hash chain */
int un_refs; /* c: Reference counter */ int un_refs; /* c: Reference counter */
struct mount *un_mount; /* c: union mount */
struct vnode *un_vnode; /* :: Back pointer */ struct vnode *un_vnode; /* :: Back pointer */
struct vnode *un_uppervp; /* m: overlaying object */ struct vnode *un_uppervp; /* m: overlaying object */
struct vnode *un_lowervp; /* v: underlying object */ struct vnode *un_lowervp; /* v: underlying object */
@ -162,6 +163,8 @@ extern void union_newupper(struct union_node *, struct vnode *);
extern void union_newsize(struct vnode *, off_t, off_t); extern void union_newsize(struct vnode *, off_t, off_t);
int union_readdirhook(struct vnode **, struct file *, struct lwp *); int union_readdirhook(struct vnode **, struct file *, struct lwp *);
VFS_PROTOS(union);
#define MOUNTTOUNIONMOUNT(mp) ((struct union_mount *)((mp)->mnt_data)) #define MOUNTTOUNIONMOUNT(mp) ((struct union_mount *)((mp)->mnt_data))
#define VTOUNION(vp) ((struct union_node *)(vp)->v_data) #define VTOUNION(vp) ((struct union_node *)(vp)->v_data)
#define UNIONTOV(un) ((un)->un_vnode) #define UNIONTOV(un) ((un)->un_vnode)

225
sys/fs/union/union_subr.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: union_subr.c,v 1.69 2015/02/16 10:21:25 hannken Exp $ */ /* $NetBSD: union_subr.c,v 1.70 2015/02/16 10:22:00 hannken Exp $ */
/* /*
* Copyright (c) 1994 * Copyright (c) 1994
@ -72,7 +72,7 @@
*/ */
#include <sys/cdefs.h> #include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.69 2015/02/16 10:21:25 hannken Exp $"); __KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.70 2015/02/16 10:22:00 hannken Exp $");
#include <sys/param.h> #include <sys/param.h>
#include <sys/systm.h> #include <sys/systm.h>
@ -344,22 +344,12 @@ union_rele(struct union_node *un)
* the reference is either maintained in the new union_node * the reference is either maintained in the new union_node
* object which is allocated, or they are vrele'd. * object which is allocated, or they are vrele'd.
* *
* all union_nodes are maintained on a singly-linked * all union_nodes are maintained on a hash
* list. new nodes are only allocated when they cannot * list. new nodes are only allocated when they cannot
* be found on this list. entries on the list are * be found on this list. entries on the list are
* removed when the vfs reclaim entry is called. * removed when the vfs reclaim entry is called.
* *
* a single lock is kept for the entire list. this is * the vnode gets attached or referenced with vcache_get().
* needed because the getnewvnode() function can block
* waiting for a vnode to become free, in which case there
* may be more than one process trying to get the same
* vnode. this lock is only taken if we are going to
* call getnewvnode, since the kernel itself is single-threaded.
*
* if an entry is found on the list, then call vget() to
* take a reference. this is done because there may be
* zero references to it and so it needs to removed from
* the vnode free list.
*/ */
int int
union_allocvp( union_allocvp(
@ -373,14 +363,9 @@ union_allocvp(
int docache) int docache)
{ {
int error; int error;
struct vattr va;
struct union_node *un = NULL, *un1; struct union_node *un = NULL, *un1;
struct vnode *vp, *xlowervp = NULLVP; struct vnode *vp, *xlowervp = NULLVP;
struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
voff_t uppersz, lowersz;
dev_t rdev;
u_long hash[3]; u_long hash[3];
int vflag, iflag;
int try; int try;
bool is_dotdot; bool is_dotdot;
@ -394,20 +379,6 @@ union_allocvp(
lowervp = NULLVP; lowervp = NULLVP;
} }
/* detect the root vnode (and aliases) */
iflag = VI_LAYER;
vflag = 0;
if ((uppervp == um->um_uppervp) &&
((lowervp == NULLVP) || lowervp == um->um_lowervp)) {
if (lowervp == NULLVP) {
lowervp = um->um_lowervp;
if (lowervp != NULLVP)
vref(lowervp);
}
iflag = 0;
vflag = VV_ROOT;
}
if (!docache) { if (!docache) {
un = NULL; un = NULL;
goto found; goto found;
@ -434,17 +405,18 @@ loop:
LIST_FOREACH(un, &uhashtbl[hash[try]], un_cache) { LIST_FOREACH(un, &uhashtbl[hash[try]], un_cache) {
if ((un->un_lowervp && un->un_lowervp != lowervp) || if ((un->un_lowervp && un->un_lowervp != lowervp) ||
(un->un_uppervp && un->un_uppervp != uppervp) || (un->un_uppervp && un->un_uppervp != uppervp) ||
UNIONTOV(un)->v_mount != mp) un->un_mount != mp)
continue; continue;
vp = UNIONTOV(un);
union_ref(un); union_ref(un);
mutex_enter(vp->v_interlock);
mutex_exit(&uhash_lock); mutex_exit(&uhash_lock);
error = vget(vp, 0); error = vcache_get(mp, &un, sizeof(un), &vp);
KASSERT(error != 0 || UNIONTOV(un) == vp);
union_rele(un); union_rele(un);
if (error) if (error == ENOENT)
goto loop; goto loop;
else if (error)
goto out;
goto found; goto found;
} }
} }
@ -492,77 +464,15 @@ found:
*vpp = UNIONTOV(un); *vpp = UNIONTOV(un);
if (uppervp != dvp) if (uppervp != dvp)
VOP_UNLOCK(*vpp); VOP_UNLOCK(*vpp);
return (0); error = 0;
goto out;
} }
uppersz = lowersz = VNOVAL; un = malloc(sizeof(struct union_node), M_TEMP, M_WAITOK);
if (uppervp != NULLVP) {
vn_lock(uppervp, LK_SHARED | LK_RETRY);
if (VOP_GETATTR(uppervp, &va, FSCRED) == 0)
uppersz = va.va_size;
VOP_UNLOCK(uppervp);
}
if (lowervp != NULLVP) {
vn_lock(lowervp, LK_SHARED | LK_RETRY);
if (VOP_GETATTR(lowervp, &va, FSCRED) == 0)
lowersz = va.va_size;
VOP_UNLOCK(lowervp);
}
/*
* Get a new vnode and share the lock with upper layer vnode,
* unless layers are inverted.
*/
vnode_t *svp = (uppervp != NULLVP) ? uppervp : lowervp;
error = getnewvnode(VT_UNION, mp, union_vnodeop_p,
svp->v_interlock, vpp);
if (error) {
if (uppervp)
vrele(uppervp);
if (lowervp)
vrele(lowervp);
return error;
}
if (docache) {
mutex_enter(&uhash_lock);
LIST_FOREACH(un1, &uhashtbl[hash[0]], un_cache) {
if (un1->un_lowervp == lowervp &&
un1->un_uppervp == uppervp &&
UNIONTOV(un1)->v_mount == mp) {
/*
* Another thread beat us, push back freshly
* allocated vnode and retry.
*/
mutex_exit(&uhash_lock);
ungetnewvnode(*vpp);
goto loop;
}
}
}
(*vpp)->v_data = malloc(sizeof(struct union_node), M_TEMP, M_WAITOK);
(*vpp)->v_vflag |= vflag;
(*vpp)->v_iflag |= iflag;
rdev = NODEV;
if (uppervp) {
(*vpp)->v_type = uppervp->v_type;
if (uppervp->v_type == VCHR || uppervp->v_type == VBLK)
rdev = uppervp->v_rdev;
} else {
(*vpp)->v_type = lowervp->v_type;
if (lowervp->v_type == VCHR || lowervp->v_type == VBLK)
rdev = lowervp->v_rdev;
}
if (rdev != NODEV)
spec_node_init(*vpp, rdev);
un = VTOUNION(*vpp);
mutex_init(&un->un_lock, MUTEX_DEFAULT, IPL_NONE); mutex_init(&un->un_lock, MUTEX_DEFAULT, IPL_NONE);
un->un_refs = 1; un->un_refs = 1;
un->un_vnode = *vpp; un->un_mount = mp;
un->un_vnode = NULL;
un->un_uppervp = uppervp; un->un_uppervp = uppervp;
un->un_lowervp = lowervp; un->un_lowervp = lowervp;
un->un_pvp = undvp; un->un_pvp = undvp;
@ -572,10 +482,8 @@ found:
un->un_openl = 0; un->un_openl = 0;
un->un_cflags = 0; un->un_cflags = 0;
mutex_enter(&un->un_lock);
un->un_uppersz = VNOVAL; un->un_uppersz = VNOVAL;
un->un_lowersz = VNOVAL; un->un_lowersz = VNOVAL;
union_newsize(*vpp, uppersz, lowersz);
if (dvp && cnp && (lowervp != NULLVP)) { if (dvp && cnp && (lowervp != NULLVP)) {
un->un_path = malloc(cnp->cn_namelen+1, M_TEMP, M_WAITOK); un->un_path = malloc(cnp->cn_namelen+1, M_TEMP, M_WAITOK);
@ -589,17 +497,36 @@ found:
} }
if (docache) { if (docache) {
mutex_enter(&uhash_lock);
LIST_FOREACH(un1, &uhashtbl[hash[0]], un_cache) {
if (un1->un_lowervp == lowervp &&
un1->un_uppervp == uppervp &&
un1->un_mount == mp) {
/*
* Another thread beat us, push back freshly
* allocated node and retry.
*/
mutex_exit(&uhash_lock);
union_rele(un);
goto loop;
}
}
LIST_INSERT_HEAD(&uhashtbl[hash[0]], un, un_cache); LIST_INSERT_HEAD(&uhashtbl[hash[0]], un, un_cache);
un->un_cflags |= UN_CACHED; un->un_cflags |= UN_CACHED;
mutex_exit(&uhash_lock);
} }
error = vcache_get(mp, &un, sizeof(un), vpp);
KASSERT(error != 0 || UNIONTOV(un) == *vpp);
union_rele(un);
if (error == ENOENT)
goto loop;
out:
if (xlowervp) if (xlowervp)
vrele(xlowervp); vrele(xlowervp);
if (docache) return error;
mutex_exit(&uhash_lock);
return (error);
} }
int int
@ -607,9 +534,83 @@ union_freevp(struct vnode *vp)
{ {
struct union_node *un = VTOUNION(vp); struct union_node *un = VTOUNION(vp);
vcache_remove(vp->v_mount, &un, sizeof(un));
mutex_enter(vp->v_interlock);
vp->v_data = NULL;
mutex_exit(vp->v_interlock);
union_rele(un); union_rele(un);
vp->v_data = NULL; return 0;
}
int
union_loadvnode(struct mount *mp, struct vnode *vp,
const void *key, size_t key_len, const void **new_key)
{
struct vattr va;
struct vnode *svp;
struct union_node *un;
struct union_mount *um;
voff_t uppersz, lowersz;
KASSERT(key_len == sizeof(un));
memcpy(&un, key, key_len);
um = MOUNTTOUNIONMOUNT(mp);
svp = (un->un_uppervp != NULLVP) ? un->un_uppervp : un->un_lowervp;
vp->v_tag = VT_UNION;
vp->v_op = union_vnodeop_p;
vp->v_data = un;
un->un_vnode = vp;
vp->v_type = svp->v_type;
if (svp->v_type == VCHR || svp->v_type == VBLK)
spec_node_init(vp, svp->v_rdev);
mutex_obj_hold(svp->v_interlock);
uvm_obj_setlock(&vp->v_uobj, svp->v_interlock);
vp->v_iflag |= VI_LOCKSHARE;
/* detect the root vnode (and aliases) */
if ((un->un_uppervp == um->um_uppervp) &&
((un->un_lowervp == NULLVP) || un->un_lowervp == um->um_lowervp)) {
if (un->un_lowervp == NULLVP) {
un->un_lowervp = um->um_lowervp;
if (un->un_lowervp != NULLVP)
vref(un->un_lowervp);
}
vp->v_vflag |= VV_ROOT;
} else {
vp->v_iflag |= VI_LAYER;
}
uppersz = lowersz = VNOVAL;
if (un->un_uppervp != NULLVP) {
if (vn_lock(un->un_uppervp, LK_SHARED) == 0) {
if (VOP_GETATTR(un->un_uppervp, &va, FSCRED) == 0)
uppersz = va.va_size;
VOP_UNLOCK(un->un_uppervp);
}
}
if (un->un_lowervp != NULLVP) {
if (vn_lock(un->un_lowervp, LK_SHARED) == 0) {
if (VOP_GETATTR(un->un_lowervp, &va, FSCRED) == 0)
lowersz = va.va_size;
VOP_UNLOCK(un->un_lowervp);
}
}
mutex_enter(&un->un_lock);
union_newsize(vp, uppersz, lowersz);
mutex_enter(&uhash_lock);
union_ref(un);
mutex_exit(&uhash_lock);
*new_key = &vp->v_data;
return 0; return 0;
} }

7
sys/fs/union/union_vfsops.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: union_vfsops.c,v 1.73 2014/10/18 08:33:29 snj Exp $ */ /* $NetBSD: union_vfsops.c,v 1.74 2015/02/16 10:22:00 hannken Exp $ */
/* /*
* Copyright (c) 1994 The Regents of the University of California. * Copyright (c) 1994 The Regents of the University of California.
@ -77,7 +77,7 @@
*/ */
#include <sys/cdefs.h> #include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.73 2014/10/18 08:33:29 snj Exp $"); __KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.74 2015/02/16 10:22:00 hannken Exp $");
#include <sys/param.h> #include <sys/param.h>
#include <sys/systm.h> #include <sys/systm.h>
@ -98,8 +98,6 @@ __KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.73 2014/10/18 08:33:29 snj Exp $"
MODULE(MODULE_CLASS_VFS, union, NULL); MODULE(MODULE_CLASS_VFS, union, NULL);
VFS_PROTOS(union);
static struct sysctllog *union_sysctl_log; static struct sysctllog *union_sysctl_log;
/* /*
@ -518,6 +516,7 @@ struct vfsops union_vfsops = {
.vfs_statvfs = union_statvfs, .vfs_statvfs = union_statvfs,
.vfs_sync = union_sync, .vfs_sync = union_sync,
.vfs_vget = union_vget, .vfs_vget = union_vget,
.vfs_loadvnode = union_loadvnode,
.vfs_fhtovp = (void *)eopnotsupp, .vfs_fhtovp = (void *)eopnotsupp,
.vfs_vptofh = (void *)eopnotsupp, .vfs_vptofh = (void *)eopnotsupp,
.vfs_init = union_init, .vfs_init = union_init,